KR102586489B1 - Brake system of vehicle and method for controlling the same - Google Patents

Abstract

The present invention relates to a brake device for a vehicle, which can stably perform an EPB cooperative control process such as a dynamic parking brake when a vehicle equipped with an electric booster enters the backup mode due to a device abnormality or failure related to the booster. The main purpose is to provide a brake system for vehicles that can operate. In order to achieve the above object, a vehicle brake device including a fallback valve installed in a hydraulic supply line connected to the wheel brake of a vehicle equipped with an electronic parking brake and selectively blocking the supply of brake hydraulic pressure to the wheel brake, and The control method is disclosed.

Description

Brake system of vehicle and method for controlling the same}

The present invention relates to a vehicle braking device and its control method, and more specifically, to an EPB for dynamic parking braking when a vehicle equipped with an electric booster enters the backup mode due to a problem or malfunction of the device related to the booster. It relates to a vehicle braking device and its control method that can stably perform a cooperative control process.

Typically, a vehicle's brake system includes a booster, that is, a brake booster, installed between the brake pedal and the master cylinder, which increases the pedal operation force (i.e., pedal effort), which is the force applied to the brake pedal by the driver, to increase the master cylinder. delivered to the cylinder.

Normally, the brake booster is designed to increase the brake pedal operation force by using the pressure difference between the vacuum pressure (negative pressure) provided on the intake side of the engine and the atmospheric pressure, and the amplified force is generated by combining the master cylinder with the front cell that forms the positive pressure chamber. It allows you to generate hydraulic pressure using .

This brake booster includes an input rod that receives force from the brake pedal and an output rod that outputs increased force, and produces a force greater than the input when the driver presses the brake pedal, that is, an output greater than the force applied to the brake pedal. is transmitted to the master cylinder through the output rod so that hydraulic pressure can be smoothly generated in the master cylinder.

As a result, the brake booster reduces the force required when the driver operates the brake pedal.

Meanwhile, an integrated electric booster (IEB) that uses an electric motor as a booster to reduce the force required to operate the brake pedal is known.

This electric booster (IEB) is an electric device that uses the power of an electric motor rather than the negative pressure of a mechanical engine to increase power. When the control element controls the operation of the electric motor based on the amount of brake pedal operation detected by the sensor, At this time, the piston moves forward due to the rotational movement of the electric motor so that the necessary hydraulic pressure can be generated within the master cylinder.

In this way, the electric booster has the advantage of being applicable to eco-friendly vehicles without engines, such as electric vehicles, because it does not need to use engine negative pressure. However, since it is an electric system rather than a mechanical system, it can be used in backup mode (backup mode) due to electrical effects such as low voltage or circuit burnout. There is a high possibility that it will switch to backup mode.

However, when the backup mode actually occurs, braking assistance is required due to a rapid decrease in braking deceleration.

In backup mode, there is a risk of a collision accident due to lack of braking power, and even if you enter backup mode after detecting a fail, you only need to meet a certain level of legal specifications, so although the actual law is satisfied in a fail situation, the brake pedal must be used. When operating, the driver may feel as if the actual initial pedal operation becomes hard and at the same time the vehicle's braking deceleration is barely formed.

Therefore, as a solution to the above problem, when switching to backup mode in a vehicle equipped with an integrated electric booster (IEB), braking and deceleration are performed using the electronic parking brake (hereinafter referred to as 'EPB') on the rear wheels. Measures to provide assistance may be considered.

In other words, the dynamic parking brake technology, which is an additional function of the EPB caliper on the rear wheels, is used to assist the vehicle's braking deceleration in backup mode when the vehicle is driving, not when parked.

However, in a vehicle equipped with a conventional integrated electric booster (IEB), it is very difficult to perform cooperative control to assist braking deceleration with actual dynamic parking braking of EBP in backup mode.

In the backup mode, the cut valve, which is a normally open (NO) type valve, remains open, so when the driver steps on the brake pedal at this time, the hydraulic pressure caused by the pedal effort is also transmitted to the caliper of the rear wheel. In this state, where hydraulic pressure is already formed inside the caliper of the rear wheel, it is difficult to perform EPB coordination control, that is, dynamic parking braking control.

If the hydraulic pressure of the master cylinder due to the driver's pedal pressure is transmitted to the rear caliper, EPB cooperative control that generates braking force in the EPB, that is, cooperative control in which the EPB actuator separately applies force to the rear caliper, is performed. Rear wheel lock may occur, which may cause the vehicle to lose stability and turn.

For this reason, it is very difficult in reality to perform EPB cooperative control for dynamic parking braking in the backup mode in a conventional braking device using an electric booster (IEB).

Therefore, the present invention was created to solve the above problems, and the EPB cooperative control process for dynamic parking braking when a device abnormality or failure related to the electric booster, such as low voltage or circuit burnout, occurs and enters the backup mode. The purpose is to provide a vehicle braking device and a control method that can stably perform.

In order to achieve the above object, according to one aspect of the present invention, there is a brake device for a vehicle equipped with an electric booster and an electronic parking brake (EPB), which receives the pedal pressure output from the electric booster to apply brake hydraulic pressure. a master cylinder that generates; A hydraulic pressure supply device that generates and supplies brake fluid pressure according to the driver pedal operation value detected by the brake pedal sensor; A hydraulic supply line connected to the wheel brake of each wheel to enable supply of brake hydraulic pressure from the hydraulic pressure supply device; A backup line connected to the hydraulic supply line to enable supply of brake fluid pressure from the master cylinder; A cut valve installed in the backup line to selectively block brake fluid pressure; and a fallback valve installed in a hydraulic supply line connected to a wheel brake of a vehicle equipped with an electronic parking brake to selectively block the supply of brake fluid pressure to the wheel brake.

And, according to another aspect of the present invention, in a vehicle equipped with an electric booster and an electronic parking brake (EPB: Electronic Parking Brake), a master cylinder that generates brake hydraulic pressure by receiving the pedal effort output from the electric booster; A hydraulic pressure supply device that generates and supplies brake fluid pressure according to the driver pedal operation value detected by the brake pedal sensor; A hydraulic supply line connected from the hydraulic supply device to the wheel brake of each wheel; A backup line connected from the master cylinder to the hydraulic supply line; A cut valve installed in the backup line to selectively block brake fluid pressure; and a fallback valve installed in the hydraulic supply line connected to the wheel brake of the wheel on which the electronic parking brake is installed to selectively block the supply of brake fluid pressure to the wheel brake, wherein the controller includes an electric booster. Diagnosing the state of the brake device and entering a backup mode if it is in a malfunction state when the driver operates the brake pedal; As the driver operates the brake pedal, brake fluid pressure is generated in the master cylinder according to the pedal effort; Controlling the fallback valve to be closed by the controller in the backup mode entry state; and performing dynamic parking brake control by a controller to generate braking force for vehicle deceleration using an electronic parking brake.

And, according to another aspect of the present invention, in a vehicle equipped with an electric booster and an electronic parking brake (EPB) on the rear wheels, a fallback valve is installed separately from the cut valve in the hydraulic line between the master cylinder and the wheel brakes on the rear wheels. A method of controlling a brake device, comprising: a controller diagnosing the state of a brake device including an electric booster and entering a backup mode when a driver operates the brake pedal in a malfunction state; As the driver operates the brake pedal, brake fluid pressure is generated in the master cylinder according to the pedal effort; Controlling the fallback valve to be closed by the controller in the backup mode entry state; and performing dynamic parking brake control by a controller to generate braking force for vehicle deceleration using an electronic parking brake.

Accordingly, according to the brake device and its control method according to the present invention, the EPB cooperative control process such as dynamic parking braking can be stably performed while entering the backup mode of the integrated electric booster, so there is no vehicle braking deceleration in the backup mode. It is possible to avoid concerns about collisions and accidents due to this, and the vehicle's braking performance and driving stability can be improved.

In addition, according to the brake device and its control method according to the present invention, simple improvements such as adding a valve capable of blocking the circuit in the backup mode in the hydraulic circuit of the brake device using an electric booster (IEB) It is possible to improve braking deceleration and thereby secure stability.

1 is a configuration diagram showing a brake device for a vehicle according to the prior art.
Figure 2 is a configuration diagram showing a vehicle brake device according to an embodiment of the present invention.
Figure 3 is a block diagram showing the main components of a brake device according to an embodiment of the present invention.
Figure 4 is a flowchart showing the control process of a brake device according to an embodiment of the present invention.

Hereinafter, with reference to the attached drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms.

Throughout the specification, when a part is said to “include” a certain element, this means that it may further include other elements rather than excluding other elements, unless specifically stated to the contrary.

In order to facilitate understanding of the present invention, the configuration and problems of a brake device according to the prior art will first be described with reference to the drawings.

Figure 1 is a block diagram showing a brake device of a vehicle according to the prior art, illustrating a hydraulic circuit in which brake hydraulic pressure is generated as the driver operates the brake pedal 2, and hydraulic pressure being supplied from the hydraulic circuit. Lines (6,8) are shown as thick lines.

Figure 1 shows a state in which the brake fluid pressure due to pedal effort is transmitted to both the wheel brakes 28 of the front wheels (FL, FR) and the wheel brakes 28 of the rear wheels (RL, RR) in the backup mode. In this state, Dynamic parking and braking control becomes practically impossible.

As shown, the brake device includes a reservoir (1) in which brake fluid is stored, a master cylinder (4) that generates hydraulic pressure when the driver operates the brake pedal (2), and the driver's pressure by the hydraulic pressure generated in the master cylinder (4). A pedal simulator (12) that provides pedal feel according to pedal effort, a wheel brake (28) installed on each wheel (FL, FR, RL, RR), and a hydraulic pressure supply device (20) that generates brake hydraulic pressure. , and hydraulic lines (6, 8, 8a, 23, 24) connecting parts such as the reservoir (1), the master cylinder (4), the pedal simulator (12), the hydraulic supply device (20), and the wheel brake (28). ), and valves (7, 9, 25, 26, 27) installed on the hydraulic line.

In Figure 1, reference numeral 3 represents a brake pedal sensor (Pedal Travel Sensor, PTS), reference numerals 5a and 5b represent hydraulic ports through which hydraulic pressure is discharged from the master cylinder 4, and reference numeral 21 represents a hydraulic pressure supply device (20). ) represents the hydraulic cylinder, and reference numeral 22 represents the piston of the hydraulic pressure supply device (20).

Additionally, in FIG. 1, reference numeral M represents a motor of the hydraulic pressure supply device 20, and reference numeral T represents a power conversion unit of the hydraulic pressure supply device 20.

Referring to FIG. 1, in a conventional brake device, when entering the backup mode, the cut valves (7, 9) are open, so the wheels installed on the front wheels (FL, FR) and rear wheels (RL, RR) To all of the calipers (wheel cylinders) of the brake 28, brake fluid pressure (master cylinder hydraulic pressure) generated by pedal effort can be supplied through hydraulic lines 6 and 8.

In a vehicle equipped with an electric booster (not shown), for example, a known integrated electric booster (IEB), when the electric booster cannot be used due to device abnormalities or failures such as low voltage or circuit burnout, backup mode is used. After entering, power is not applied to all valves in the conventional brake device as shown.

Accordingly, the cut valves 7 and 9, which are normally open (NO) type, are in an open state, and at this time, when the driver steps on the brake pedal 2, the driver's pedal effort causes pressure in the master cylinder 4. The generated brake fluid pressure (hydraulic pressure) is directly transmitted to the caliper of the wheel brake 28 installed on each wheel (FL, FR, RL, RR).

At this time, the brake fluid pressure (hydraulic pressure) generated in the master cylinder 4 by the driver's pedal effort is transmitted to the wheel brakes 28 of the rear wheels (RL, RR), and more specifically to the calipers of the rear wheel brakes, It is impossible to accurately and precisely control the operation of the electronic parking brake (not shown) (hereinafter referred to as 'EPB').

To explain in more detail, in the backup mode, when the driver operates the brake pedal (2) in a running vehicle to generate braking force not only on the front wheels but also on the rear wheels, the operation of the rear EPB is precisely controlled for stable vehicle braking. It may be considered to perform EPB coordinated control (dynamic parking brake control), which generates braking force on the rear wheels at a level that does not cause rear wheel lock, but in backup mode, the cut valve (7,9 ) is open, so the brake fluid pressure of the master cylinder (4) is directly transmitted to the calipers of the rear wheels (RL, RR).

In this way, if the brake fluid pressure (i.e., master cylinder hydraulic pressure) generated by the driver's pedal effort is applied to and formed in the calipers on both rear wheels (RL, RR), hydraulic pressure is already acting on the pistons in the cylinders of the calipers on both rear wheels. Therefore, in this state, forward and backward control of the piston by the EPB actuator cannot be properly performed.

In other words, because the brake hydraulic pressure and the force generated by the EPB actuator (usually an electric motor) (the force of the EPB actuator transmitted through the gear device) act simultaneously on the piston in the cylinder of the caliper, it is difficult to control the piston forward and backward, especially the rear wheel. EPB cooperative control, which controls the operation of the EPB to generate braking force at a level that does not cause locking, is difficult.

In backup mode, if hydraulic pressure from the driver's pedal effort is already formed in the calipers on both rear wheels, when performing EPB cooperative control for dynamic parking braking, the forward and backward movement of the piston by the EPB actuator is at the required level. It cannot be controlled accurately.

Ultimately, in the worst case, the braking torque can instantaneously reach the level of rear wheel lock due to the brake fluid pressure (master cylinder hydraulic pressure) generated by the pedal effort from the caliper of the rear wheel and the force generated by the actuator (motor force). Wheel lock may cause the vehicle to turn.

Therefore, the present invention is intended to solve the above problems, and is a brake device and its hydraulic circuit that can stably perform EPB coordinated control for dynamic parking braking after entering the backup mode in a vehicle equipped with an integrated electric booster (IEB). It is intended to provide.

The present invention can be applied to vehicles equipped with an electric booster (IEB) and an electronic parking brake (hereinafter referred to as 'EPB'). When the driver presses the brake pedal while the vehicle is driving after entering the backup mode, The main technical feature is that the brake hydraulic pressure (master cylinder hydraulic pressure) to the rear wheel can be blocked using a separate valve, allowing EPB cooperative control for dynamic parking braking to be performed stably even in backup mode.

In general, in normal mode rather than backup mode in vehicles equipped with EPB, when the driver presses the brake pedal while the vehicle is running, the EPB is precisely controlled to generate the required braking force when the vehicle decelerates at a level that does not cause rear wheel lock. EPB coordinated control (dynamic parking brake control) can be performed.

In this way, braking that uses EPB to generate braking force to decelerate the vehicle when the vehicle is in a driving state rather than parked can be called dynamic parking braking. On the other hand, when the vehicle is parked, EPB is used to brake the wheels to prevent the vehicle from moving. Braking with the original purpose of fixing it can be called static parking braking.

In the case of normal mode in a conventional brake device, the cut valves (7, 9) can be kept closed (clsoed) by applying current, and through this, the hydraulic pressure of the master cylinder (4) is applied to the wheels of the rear wheels (RL, RR). It can be prevented from being transmitted to the brake 28 (caliper), and in this state, it is possible to perform EPB cooperative control for dynamic parking braking.

On the other hand, in the backup mode, the current is blocked and the normally open type cut valves (7, 9) are opened, so the hydraulic pressure of the master cylinder (4) can be transmitted to the wheel brakes (28) of the rear wheels (RL, RR). , It is difficult to perform EPB cooperative control for dynamic parking braking in a state where rear wheel hydraulic pressure is already formed.

Accordingly, in the present invention, in the case of the backup mode, an additional valve is used to block the hydraulic pressure to the rear wheel brake, so that EPB cooperative control for dynamic parking braking can be stably performed, and the backup mode is enabled through stable EPB cooperative control. This helps avoid the risk of collision due to insufficient braking deceleration.

Hereinafter, a vehicle braking device and a control method thereof according to an embodiment of the present invention will be described in detail with reference to the drawings, and will be described with reference to an embodiment in which an EPB is mounted on the rear wheel of the vehicle.

Figure 2 is a configuration diagram showing a brake device of a vehicle according to an embodiment of the present invention, and brake fluid pressure due to pedal pressure is transmitted to the wheel brakes 28 on both sides of the rear wheels (RL, RR) by the fallback valve 29. It shows that the rear wheel hydraulic pressure is blocked.

Figure 3 is a block diagram showing the main components of the brake device according to an embodiment of the present invention, and Figure 4 is a flow chart showing the control process of the brake device according to an embodiment of the present invention.

The brake device according to an embodiment of the present invention is not shown in FIG. 2, but as shown in FIG. 3, it includes an integrated electric booster (IEB) 11 and an electronic parking brake (hereinafter referred to as 'EPB') 30. It can be.

In addition, the brake device according to an embodiment of the present invention includes an additional valve, that is, a fallback valve 29, that can selectively block the hydraulic pressure for the wheel brakes 28 of the rear wheels RL and RR. , Except for the fallback valve 29, there is no difference in the remaining components compared to the conventional brake device described with reference to FIG. 1.

That is, the brake device according to the embodiment of the present invention includes a reservoir 1 in which brake fluid (brake oil) is stored, and increased driver pedal effort output from the electric booster 11 when the driver operates the brake pedal 2. It may include a master cylinder 4 that receives approval and generates hydraulic pressure, and a pedal simulator 12 that provides pedal feel according to the driver's pedal effort by the hydraulic pressure generated in the master cylinder 4.

In addition, the brake device according to an embodiment of the present invention includes a wheel brake 28 installed on each wheel (FL, FR, RL, RR), a hydraulic pressure supply device 20 that generates brake hydraulic pressure (braking hydraulic pressure), and Hydraulic lines (6, 8, 8a, 23, 24) connecting parts such as reservoir (1), master cylinder (4), pedal simulator (12), hydraulic pressure supply device (20), and wheel brake (28), And it may further include valves (7, 9, 25, 26, 27) installed in the hydraulic line.

The pedal simulator 12 is connected to the master cylinder 4 and the backup line 8a to receive hydraulic pressure generated by the master cylinder 4.

In addition, the brake device according to an embodiment of the present invention may have a configuration that forms and controls hydraulic pressure with an electronic actuator, and such a brake device is commonly referred to as an Electro-Hydraulic Brake System (EHB), that is, an electro-hydraulic brake device.

Figure 2 shows the configuration of an electro-hydraulic brake device as an example. This is an example and does not limit the present invention, and the present invention is a general hydraulic brake device that generates and supplies brake hydraulic pressure with a typical pump instead of an electronic actuator. It may have the configuration of a brake device.

As shown, the electronic hydraulic brake device uses an electronic hydraulic actuator as a hydraulic pressure supply device 20 that generates and supplies brake hydraulic pressure (braking hydraulic pressure).

The electronic hydraulic actuator, which is the hydraulic pressure supply device 20, converts the rotational force generated and provided by the motor (M) into linear force through the power conversion unit (T) to move the piston 22 forward and backward, at this time , The piston 22, which is controlled backwards, may have a configuration that generates and controls hydraulic pressure by pressurizing the brake fluid in the chamber of the cylinder 21.

That is, when the driver operates the brake pedal (2), the pedal operation value is detected through the brake pedal sensor (PTS) (3), and the controller (reference numeral 10 in FIG. 3) operates the actuator according to the detected pedal operation value. When controlling the motor (M) of the (hydraulic pressure supply device) 20, the rotational force of the motor (M) is converted into linear force by the power conversion unit (T) to move the piston 22 forward and backward, thereby moving the cylinder 21 ), a regulated hydraulic pressure is generated within.

Since the electronic actuator described above is a known configuration already used in an electronic hydraulic brake system (EHB), further description thereof will be omitted.

In the brake device according to the embodiment of the present invention, the wheel brake 28 is a hydraulic pressure supply device that transmits the brake hydraulic pressure (braking hydraulic pressure) generated by the hydraulic pressure supply device 20 to generate braking force to restrain the rotation of the corresponding wheel. (20) is connected through hydraulic lines (23, 24).

In the brake device according to the embodiment of the present invention, the hydraulic line is connected between the hydraulic pressure supply device 20 and the wheel brake 28 of each wheel to supply brake hydraulic pressure (braking hydraulic pressure) generated by the hydraulic pressure supply device 20. It includes hydraulic supply lines (23, 24) supplied to each wheel brake (28), and backup lines (6, 8) connected from the master cylinder (4) to the hydraulic supply lines (23, 24).

The hydraulic supply line is a first hydraulic supply line 23 connected from the hydraulic pressure supply device (electronic hydraulic actuator) 20 to the two wheel brakes 28 of the front wheels (FL, FR), and a first hydraulic supply line 23 connected to the hydraulic pressure supply device 20. It includes a second hydraulic supply line (24) connected to the two wheel brakes (28) of the rear wheels (RL, RR).

Valves 25 that control the flow of brake fluid are installed in the hydraulic supply lines 23 and 24 between the hydraulic pressure supply device 20 and the wheel brake 28.

In addition, each of the hydraulic supply lines 23 and 24 is connected to the wheel brake 28 of each wheel (FL, FR, RL, RR) through the inlet valve 26, and the hydraulic pressure is connected to the wheel brake of each wheel. An outlet valve 27 is installed in the return line branched from the supply lines 23 and 24.

In addition, the backup line includes a first backup line (6) connected from the first hydraulic port (5a) of the master cylinder (4) to the first hydraulic supply line (23), and a second hydraulic port of the master cylinder (4). It includes a second backup line (8) connected to the second hydraulic supply line (24) at (5b).

In addition, a first cut valve (7) is installed in the first backup line (6), a second cut valve (9) is installed in the second backup line (8), and the first cut valve (7) and the second cut valve (7) are installed in the first backup line (6). The cut valves 9 are all normally open type valves.

In this configuration, the first backup line 6 and the second backup line 8 are part of the hydraulic line between the master cylinder 4 and the wheel brake 28, and are the first backup line ( 6) and the second backup line (8) are in a state where the first cut valve (7) and the second cut valve (9) are open (current blocked state) when entering the backup mode due to a failure of the brake device, etc. ) and serves to transmit the hydraulic pressure generated in the master cylinder (4) to each wheel brake (28).

On the other hand, in normal mode, the first cut valve 7 and the second cut valve 9 are closed (current applied state), and at this time, the hydraulic pressure generated in the master cylinder 4 is applied to each wheel (FL, FR). ,RL,RR) is not transmitted to the wheel brake 28.

The first cut valve 7 and the second cut valve 9 connect the master cylinder 4, the pedal simulator 12, and the brake pedal 2, the hydraulic pressure supply device 20, and the hydraulic supply lines 23 and 24. ) and the wheel brake 28 and hydraulically disconnect, and when the first cut valve 7 and the second cut valve 9 are closed, the hydraulic pressure formed and controlled by the hydraulic pressure supply device 20 is It is transmitted to the wheel brake 28 of each wheel (FL, FR, RL, RR) to generate braking force.

The pedal simulator 12 is provided to provide a reaction force according to the pedal force of the brake pedal 2, and acts as a second backup between the master cylinder 3 and the second cut valve 9 through a separate hydraulic line 8a. It can be connected to line (8).

Since the configuration of the pedal simulator is a known configuration in brake devices, detailed description will be omitted.

Meanwhile, the brake device according to an embodiment of the present invention includes a fallback valve 29 that can selectively block rear wheel hydraulic pressure.

The fallback valve 29 is a new component added in the present invention, and is installed in the second hydraulic supply line 24 connected to the wheel brakes 28 (calipers) on both sides of the rear wheels (RL, RR), and is connected to the controller ( 10) It is an electronic valve that is controlled to open and close.

In more detail. The fallback valve 29 is installed in the second hydraulic supply line 24 connected from the hydraulic pressure supply device 20 to the two wheel brakes 28 on both sides of the rear wheels (RL, RR), and the second hydraulic supply line 24 ) is also installed at a location downstream from the point where the first backup line (8) is connected.

In addition, the fallback valve 29, unlike the first cut valve 7 and the second cut valve 9, is a normally closed (NC) type valve, and when current is applied by the controller 10, the fallback valve 29 is a normally closed (NC) type valve. When open and blocked without current being applied, it always remains closed.

In the present invention, in the backup mode of the electric booster 11, when both the first cut valve 7 and the second cut valve 9, which are normally open type valves, are open, the current is blocked by the controller 10. As this happens, the fallback valve 29 is closed.

As a result, the flow path of the second hydraulic supply line 24 is blocked by the fallback valve 29, so that brake hydraulic pressure cannot be supplied to the wheel brakes 28 (calipers) on both sides of the rear wheels (RL, RR). The hydraulic pressure is blocked.

When entering the backup mode, the second hydraulic supply line 24 is blocked by the fallback valve 29, so even if the driver operates the brake pedal 2, the brake fluid pressure (master cylinder hydraulic pressure) according to the pedal effort is applied to the rear wheels (RL, RR). ) is not transmitted to the wheel brakes (28) on both sides.

Ultimately, after entering the backup mode, with both the first cut valve (7) and the second cut valve (9) open, the wheel brakes (28) of the front wheels (FL, FR) apply pedal effort to the piston in the cylinder of the caliper. Brake hydraulic pressure is transmitted through the first backup line 6 and the first hydraulic supply line 23 to generate braking force.

On the other hand, in the wheel brake 28 of the rear wheels (RL, RR), the forward and backward control of the piston by the EPB actuator can be smoothly performed in a state in which the brake hydraulic pressure due to the pedal effort is not transmitted to the piston in the cylinder of the caliper. .

Therefore, the EPB cooperative control (dynamic parking brake control) is normally performed by the controller 10, so that the braking deceleration of the vehicle can be improved, and dynamic parking braking by normal EPB cooperative control allows accurate braking control for the rear wheels as well. Dynamic parking braking generates the necessary braking force to the rear wheels to assist in the vehicle's braking deceleration.

Of course, in the normal mode, current is applied to the fallback valve 29 and the fallback valve always remains open, so when the driver operates the brake pedal 2, the brake fluid pressure generated by the hydraulic pressure supply device 20 is used as the second hydraulic pressure. It can be normally supplied to the wheel brakes 28 on both sides of the rear wheels (RL, RR) through the supply line 24, and normal rear wheel braking can be achieved.

4, the diagnosis of the brake device including the electric booster 11 is performed by the controller 10, and when the brake pedal is operated by the driver, the controller 10 detects the brake from the brake pedal sensor 3. A signal indicating that the pedal (2) is operated is input.

Then, when the brake pedal is operated (S11), if it is diagnosed that an abnormality or malfunction of the electric booster 11 or a malfunction or malfunction of the brake device has occurred, the backup mode is entered (S12, S18).

Since the above diagnosis is a process already performed in known brake devices, detailed description will be omitted.

If the backup mode is entered, the controller 10 blocks the current of the fallback valve 29 so that the fallback valve is closed (S19), and thus the brake fluid pressure (hydraulic pressure of the master cylinder) caused by the pedal effort is reduced to hydraulic pressure. The rear wheel hydraulic pressure is blocked without being transmitted to the wheel brakes 28 on both sides of the rear wheels (RL, RR) through the lines 8 and 24 (S20).

In addition, when entering the backup mode, EPB cooperative control for dynamic parking braking for the rear wheels (RL, RR) can be normally performed by the controller 10 (S21), thereby allowing the front wheels (FL, FR) and the rear wheels ( Normal braking control that generates the required braking force for RL, RR) can be performed.

Of course, since the brake fluid pressure generated by the pedal effort is transmitted to the wheel brakes 28 on both sides of the front wheels (FL, FR) through the hydraulic lines 6 and 23, it is possible to generate the necessary braking force for the front wheels as well.

Meanwhile, if all brake devices including the electric booster 11 are in a normal state in step S12, current is applied to the fallback valve 29, the first cut valve 7, and the second cut valve 9 by the controller 10. The applied state is maintained, and thus the fallback valve 29, which is a normally closed type valve, is opened (S13), while the first cut valve 7 and the second cut valve 9, which is a normally open type, are closed (S14) ).

Subsequently, hydraulic pressure is generated by the operation of the hydraulic pressure supply device 20 and is transmitted to each wheel brake 28 of the front wheels (FL, FR) and rear wheels (RL, RR) (S15, S16, S17). Braking in normal mode is performed.

In this way, in the past, when a system failure occurs in a vehicle equipped with an integrated electric booster, which is an electronic system, a collision accident may occur as the driver momentarily feels a different feeling in braking (pedal hardness). However, in the brake system according to the present invention, the brake system on both sides of the rear wheel By applying an improved hydraulic circuit that can block the brake fluid pressure caused by pedal pressure for the wheel brake, EPB cooperative control for dynamic parking braking can be performed stably, strengthening the braking system and preventing field claims in advance. There is an advantage.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements can be made by those skilled in the art using the basic concept of the present invention as defined in the following patent claims. It is also included in the scope of rights of the present invention.

1: Reservoir 2: Brake pedal
3: Brake pedal sensor 4: Master cylinder
5a, 5b: Hydraulic port 6, 8: Hydraulic line
7, 9: cut valve 10: controller
11: Electric booster 12: Pedal simulator
20: Hydraulic pressure supply device 21: Hydraulic cylinder
22: Piston 23, 24: Hydraulic line
25: valve 26: inlet valve
27: outlet valve 28: wheel brake
30: Electronic parking brake

Claims (16)

A vehicle braking device equipped with an electric booster and an electronic parking brake (EPB),
A master cylinder that generates brake fluid pressure by receiving pedal pressure output from the electric booster;
A hydraulic pressure supply device that generates and supplies brake fluid pressure according to the driver pedal operation value detected by the brake pedal sensor;
A hydraulic supply line connected to the wheel brake of each wheel to enable supply of brake hydraulic pressure from the hydraulic pressure supply device;
A backup line connected to the hydraulic supply line to enable supply of brake fluid pressure from the master cylinder;
A cut valve installed in the backup line to selectively block brake fluid pressure; and
A fallback valve is installed in the hydraulic supply line connected to the wheel brake of the wheel on which the electronic parking brake is installed and includes a fallback valve to selectively block the supply of brake hydraulic pressure to the wheel brake,
The fallback valve is a brake device characterized in that it is a normally closed type valve that opens when current is applied and closes when current is cut off.
In claim 1,
The vehicle on which the electronic parking brake is installed is the rear wheel,
The fallback valve is a brake device characterized in that it is installed in a hydraulic supply line connected to supply brake fluid pressure from the hydraulic pressure supply device to the wheel brake of the rear wheel.
delete In claim 1,
The fallback valve is a brake device characterized in that it is installed at a location downstream from the point where the backup line is connected to the hydraulic supply line.
In claim 1,
The cut valve is a normally open type valve that closes when current is applied and opens when current is cut off.
In claim 1,
Further comprising a controller that controls the electronic parking brake and fallback valve,
The controller is
Diagnoses the condition of the brake device, including the electric booster, and enters a backup mode if it is in a malfunction when the driver operates the brake pedal;
A brake device characterized in that it controls the fallback valve to be closed in the backup mode entry state and simultaneously performs dynamic parking brake control to generate braking force for vehicle deceleration using an electronic parking brake.
In a vehicle equipped with an electric booster and an electronic parking brake (EPB: Electronic Parking Brake), a master cylinder that generates brake hydraulic pressure by receiving pedal pressure output from the electric booster; A hydraulic pressure supply device that generates and supplies brake fluid pressure according to the driver pedal operation value detected by the brake pedal sensor; A hydraulic supply line connected from the hydraulic supply device to the wheel brake of each wheel; A backup line connected from the master cylinder to the hydraulic supply line; A cut valve installed in the backup line to selectively block brake fluid pressure; and a fallback valve installed in a hydraulic supply line connected to the wheel brake of a vehicle equipped with an electronic parking brake to selectively block the supply of brake fluid pressure to the wheel brake. A method of controlling a brake device comprising:
A step where the controller diagnoses the state of the brake device including the electric booster and enters a backup mode if it is in a malfunction state when the driver operates the brake pedal;
As the driver operates the brake pedal, brake fluid pressure is generated in the master cylinder according to the pedal effort;
Controlling the fallback valve to be closed by the controller in the backup mode entry state; and
A control method of a brake device comprising the step of performing dynamic parking brake control by a controller to generate braking force for vehicle deceleration using an electronic parking brake.
In claim 7,
The vehicle on which the electronic parking brake is installed is the rear wheel,
A method of controlling a brake device, characterized in that the hydraulic supply line on which the fallback valve is installed is a hydraulic supply line connected to supply brake hydraulic pressure from the hydraulic pressure supply device to the wheel brake of the rear wheel.
In claim 8,
After entering the backup mode, with the cut valve open, the electronic parking brake generates braking force on the rear wheels, and at the same time, the brake fluid pressure generated in the master cylinder is transmitted to the front wheel brakes to generate braking force on the front wheels. A method of controlling a brake device.
In claim 7,
The fallback valve is a normally closed type valve that opens when current is applied and closes when the current is cut off.
In claim 7,
A method of controlling a brake device, wherein the fallback valve is installed at a location downstream of the point where the backup line is connected to the hydraulic supply line.
In claim 7,
The cut valve is a normally open type valve that closes when current is applied and opens when current is cut off.
In a vehicle equipped with an electric booster and a rear wheel electronic parking brake (EPB: Electronic Parking Brake), a control method for a brake device in which a cut valve and a separate fallback valve are installed in the hydraulic line between the master cylinder and the rear wheel brake, comprising:
A step where the controller diagnoses the state of the brake device including the electric booster and enters a backup mode if it is in a malfunction state when the driver operates the brake pedal;
As the driver operates the brake pedal, brake fluid pressure is generated in the master cylinder according to the pedal effort;
Controlling the fallback valve to be closed by the controller in the backup mode entry state; and
A control method of a brake device comprising the step of performing dynamic parking brake control by a controller to generate braking force for vehicle deceleration using an electronic parking brake.
In claim 13,
After entering the backup mode, with the cut valve installed in the hydraulic line between the master cylinder and the front wheel brake open, braking force is generated on the rear wheels by the electronic parking brake. At the same time, the brake fluid pressure generated by the master cylinder is applied to the front wheels. A control method of a brake device, characterized in that it generates braking force on the front wheels by being transmitted to the wheel brake.
In claim 13,
The fallback valve is a normally closed type valve that opens when current is applied and closes when the current is cut off.
In claim 13,
The cut valve is a normally open type valve that closes when current is applied and opens when current is cut off.

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